Drawbridge



(No Model.) 2 Sheets-Shet 1.

0. A. P. TURNER & PTA. WARNER. DRAWBRIDGE.

No. 500,633. Patented July 4, 1893.

v4 *d H l Witnesses Inventors:

W Claiidefilll'umer,

rney

(No Model.)

2 Sheets-$heet 2A 0.1. P. TURNER & P. AQWARNER. DRAWBRIDGE- o o o NITEI)STATES PATENT OFFICE.

' CLAUDE A. P. TURNER, OF ASHTON, RHODE ISLAND, AND PHILIP A. WARNER,

WEST NEWTON, MASSACHUSETTS.

DRAWBRIDG E.

SPECIFICATION forming part of Letters Patent No. 500,633, dated July 4,1893.

Application filed March 30, 1891. Serial No. 386,912. (No model.)

are termed swing bridges and it consists in a novel construction,arrangement and combination of devices for adjusting the ends of suchbridges that are applicable to a continuous or a discontinuous draw, allof which will be readily understood by reference to the description ofthe drawings and to the claims hereinafter given and in which ourinvention is clearly pointed out.

Figure 1 of the drawings is a side elevation of the central portion of adraw-bridge embodying our invention. Fig. 2 is a side ele: vation of thecentral portion of the lower chord, thelower ends of the movableinclined struts, the shoes or carriages for supporting the same, and thescrew shafts and gearing for adjusting the same drawn to an enlargedscale. Fig. 3 is an elevation of the upper portions of two pairs of saidmovable struts and the lateral strut connecting them. Fig. 4 representsa vertical section through the lower chord and the shoe or carriage online 1. 1. on Fig. 2 and shows a portion of the lower end of one of themovable inclined struts in elevation and Fig. 4* represents a transversesection of said movable strut on line 2 2 on Fig. 2. Fig. 5 is anelevation of one end of a toggle link to be used when the arms of thebridge are intended to act as simple bridges. Fig. 6 is a similar viewof an end of a toggle link to be used in a continuous draw. Fig. 7 is anelevation of a modified form of shoe or carriage, and Fig. 8 representsan arrangement of levers and rods for moving the strut supporting shoesor carriages toward and from each other.

In the drawings a is the drum of the-bearing turn-table.

b b are the main cross girders, in pairs. 0 c are the supporting girdersconnecting said main girders and serving as beds for the shoes orcarriages b Z).

d d are the longitudinal stringers; e e the lower chord. I

The chords e Q with the ports h i j and k are the truss members whichmake up the arms of the bridge.

The central portion of the upper chord of the combined truss is composedof two links or rods m m pivoted together at A and each pivoted at itsother end to the inner end of the upper chord of one of the bridge armsat B and forming a movable toggle joint at A which joint is connected tothe pivot pin which connects the upper ends of the two inclined struts n'n, the lower ends D of said struts n n being pivoted at g to the shoesor carriages b b which carriages rest upon a nest of rollers 5 see Fig.2.

The shoes or carriages b b are each provided with a nut Q, shown in Fig.4 and in dotted lines in Fig. 2 in which work the threaded ends of theScrew shaft 0 0 mounted in fixed bearings Z, Z, and provided with thrustcollars P P and the bevel gear wheel X with which the bevel gear wheel Yengages to impart rotary motion thereto.

The movable apex of truss members is at A made up of chord sections m mand struts n n. The screw Shaft 0 0 has formed thereon a right handthread at one end and a left hand thread at the other end.

The gear wheel Y is secured upon a cross shaft, not shown, to which.power is applied for working the mechanism for both trusses, thearrangement of screws and gears for the opposite truss being the sameexcept that the arrangement of the gears or the relative positions ofthe right and left screw threads must be so modified that both screwShafts will act in unison to move the shoes or carriages, and the lowerends of the struts n n of both trusses toward each other at the sametime or in like manner move them from each other at the same time.

The arrangement of the chord packing or means of connecting the chordsections m,m, to the struts n, n, is shown at A in Fig. 3 and f is thelateral strut connecting the upper ends of the struts n n. A modifiedform of shoe or carriage for supporting the struts n n is shown in Fig.7 which is applicable where.

the lower ends of the struts have to be moved through a considerabledistance which will occur when the inclination of the links m to ahorizontal plane is small.

The roll bearing of the shoes may be dispensed with in light bridges theshoe in such case being arranged to slide upon the bed without theintervention of rolls.

In some cases instead of the screw shafts 0 and nuts Q and gears X and Ywe connect to each of the shoes I) one end of a rod 0 c the oppositeends of which are connected to the levers c c and we connect to theouter ends of said levers the outer ends of the toggle links 0 0 theinner ends of which are pivoted together at 0 so that by applying powerto the joint 0 to move it in the direction indicated by the arrow 4, thestruts n, n, will be moved toward each other.

The arrangement of screws and gears or le vers for moving the shoesandthe lower ends of the struts n n will necessarily have to be modifiedsomewhat to suit the peculiar varying arrangements of the floor systemfor each particular case, but the main features and general arrangementwill remain the same.

The operation of our invention is as follows: The bridge being closedand the outer ends of the arms resting on the abutments, the shaftcarrying the gears Y is revolved in the proper direction to revolve theshafts 0 0 in such a manner as to draw the shoes b b and the ends D ofthe struts n 4% toward each other by virtue of the action of thethreaded ends of the shafts 0 0 upon the nuts Q attached to the shoes I)1), thereby moving the apex A upward and drawing the inner ends B of theupper chords of the arm trusses nearer together and raising the ends ofthe arms from contact with the abutments, when the bridge may be swungopen, and after it has again been swung to or closed the shaft carryinggear Y is revolved in the opposite direction to move the lower ends ofthe struts outward or farther from each other thereby lowering the apexA and thus permitting the ends of the arms of the bridge to fall by theforce of gravity to their bearings upon the abutments. If we provide theoblong eyes in heads A or B of bars m, and, after the outer ends of thearms have come to their bearings spread the lower ends of the struts n nstill farther we cause each arm to act as a simple bridge for live loadas well as dead weight.

The advantages of our invention are simplicity and cheapness ofconstruction, a saving of material in the trusses of short spandraw-bridges by the action of the arms as simple bridges, therebyrequiring lighter truss members in the center, and ease and certainty inthe computation of strains in the last mentioned class of draw-bridges.

In continuous structures the strains are unaifected by diiference oflevel of supports.

Another advantage is the avoidance of live load kick.

We claim 1. In combination with the two arms of a swing draw-bridge, apair of toggle links connecting the inner ends of the upper chords ofthe two arms and forming the central portion of the upper chord of themain bridge truss, a pair of movable inclined struts pivoted togetherand to said toggle links at the center of the bridge, and a system ofmechanism substantially as described for moving the bases of said strutstoward or from each other, whereby the apex of the central truss membersmay be raised or lowered thus moving the inner ends of upper chords ofthe arms toward or from each other and raising or lowering the outerends of said arms.

2. In combination with the two arms of a swing draw-bridge, a pair ofinclined struts pivoted together at their upper ends and each pivoted atits lower end to a shoe or carriage resting upon a bed and movablethereon, a pair of toggle links connecting the inner ends of the upperchords of the two bridge arms and the upper ends of said inclinedstruts, and a system of screws, nuts, gears and shafting for moving saidshoes and the lower ends of said struts toward and from each other,whereby the apex of said struts and toggle may be raised or lowered, theupper chords of the two arms of the bridge be moved toward or from eachother and the outer end of said arms be raised or lowered.

3. In combination with the two arms of a swing draw-bridge, a pair ofmovable inclined struts pivoted together at their upper ends, a pair oftoggle links each provided in one end with an oblong eye said linksbeing connected together and to the pivotal connection of the saidstruts and each pivoted at its other end to the inner end of the upperchord of one of the arms of said bridge, and a system of screws, nuts,gear and shafting for moving the lower ends of said struts toward andfrom each other substantially as and for the purposes described.

4. In combination with the two arms of a swing draw-bridge a pair ofinclined struts pivoted together at their upper ends and each pivoted atits lower end to a shoe, a nest of rollers interposed between said shoeand the bed support,'a pair of toggle links connecting the inner ends ofthe upper chords of the arm trusses and the pivotal connection of saidstruts, and a system of mechanism substantially as described for movingsaid shoes and the lower ends of said struts toward and from each. otheras described.

In testimony whereof we have signed our names to this specification, inthe presence of two subscribing witnesses, on this 23d day of March, A.D. 1891.

CLAUDE A. P. TURNER. PHILIP A. WARNER. Witnesses:

N. O. LOMBARD, WALTER E. LOMBARD.

IIO

